#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define repr(i, n) for (int i = (int)(n); i >= 0; i--)
#define all(v) v.begin(), v.end()
#define mod1 1000000007
#define mod2 998244353
typedef long long ll;

ll my_pow(ll x, ll n, ll mod){
    //　繰り返し二乗法．x^nをmodで割った余り．
    ll ret;
    if (n == 0){
        ret = 1;
    }
    else if (n % 2 == 1){
        ret = (x * my_pow((x * x) % mod, n / 2, mod)) % mod;
    }
    else{
        ret = my_pow((x * x) % mod, n / 2, mod);
    }
    return ret;
}

int main(){
    int N;
    cin >> N;
    string S;
    cin >> S;
    ll ab = 0;
    ll cd = 0;

    vector<ll> factorial(300005, 0);
    factorial[0] = 1;
    for (ll i = 0; i < 300004; i++){
        factorial[i + 1] = (factorial[i] * (i + 1)) % mod2;
    }
    for (int i = 0; i < N; i++){
        if (S[i] == 'A' || S[i] == 'B'){
            ab++;
        }
        else{
            cd++;
        }
    }
    ll ans = 1;
    ans = (ans * factorial[N]) % mod2;
    ans = (ans * my_pow(factorial[ab], mod2 - 2, mod2)) % mod2;
    ans = (ans * my_pow(factorial[cd], mod2 - 2, mod2)) % mod2;
    cout << ans << endl;
}